Normal ships of the Imperium have armoured prows, for protection upon ramming, or closing with an enemy ship, and have grey-steel paint schemes. Other ships of the Imperium also run with lights on at all times, to prevent collisions, and turn more lights on during warfare, to "illuminate the enemy." Black Ships have none of these: they run without lights, with black paint, and have blunt prows.[2] The Black Ships actually predate the Inquisition which uses them in the 41st Millennium; their presence was noted as far back as during the Horus Heresy, when Death GuardNathaniel Garro described them to himself, "[S]hips of the Astartes flotilla were swords against the enemies of Terra, a Black Ship was a hammer of witches."[2]